Machine guns with two section firing chambers



, Sept. 16, 1958 w. G. SMITHy 2,851,927

MACHINE GUNS WITH Two SECTION FIRINC CHAMBERS Filed Jan. 2'?, 1956 y s sheets-sheet 2 1N V EN TOR.

I Sept- 16, 1958 w. G. sMlTH 2,851,927

MACHINE GUNS' WITH TWOl SECTION FIRING CI-AMBERS Filed Jan. 27, 1956 3 Sheets-Sheet 3 2 -.mmprm WLM/1M SM/ rH,

IN VEN TOR.

firme/vf@ United States Patent O F MACHINE GUNS WITH TWO SECTION FRING CHAMBERS William G. Smith, Studio City, Calif., assigner, by mestre assignments, to Airtek Dynamics, Inc., Los Angeles, Calif., a corporation of Caiifornia Application January 27, 1956, Serial No. 561,737

14 Claims. (Cl. 89-33) This invention relates to improved machine guns of a type particularly designed to attain extremely rapid rates of fire, as are desired especially for aircraft purposes.

In conventional machine guns, the rate of re is rather definitely limited by the fact that upon the tiring of each round, a bolt or other part must move through a somewhat extended range of travel, for feeding the round to firing position, and properly sealing the barrel in firing condition. To reduce the distance through which the bolt or other parts must move, there has recently been proposed a telescoped type of round, in which the projectile is entirely contained within the cartridge case, so that the rounds may be much shorter than heretofore. The

general object of the present invention is to further this` advantageous result by so designing the gun mechanism itself as to reduce even more the distance through which the parts must move. j

In order to achieve this object, I employ a unique firing chamber structure which is formed of two relatively axially movable sleeves adapted to extend about and enclose opposite ends of a round, with both of the sleeves extending to approximately the center of the axial extent of a contained round. This sectionally formed ring chamber can then be opened to receive a round `by simultaneously actuating the two sleeves in opposite axial directions relative to the round and barrel, so that a round may be inserted transversely or laterally into the chamber, following which the chamber can be closed by returning the sleeves .axially toward one another. Since each of the sleeves must only move through one half the length of the round, the range of movement of the parts is just one half as great as where a single conventional bolt or other part must move the entire length of the round.

The two sleeves may be actuated automatically, upon the firing of each round, by the gases produced by the round. When the sleeves are apart, an automatic feeding mechanism acts to remove a fired round from the tiring location and advance a second round to that location. Preferably, this feeding mechanism is actuated by the movement of the firing chamber sleeves, typically through a suitable cam arrangement.

The rounds red by the gun may have seal ring portions at a longitudinally central or intermediate location, for engagement in sealing relation with the two sleeves to seal the tiring chamber. This seal ring may als-o serve as a portion of a link for interconnecting suc` cessive rounds in an ammunition belt. Desirably, the round tapers externally in opposite directions away from the ring, to facilitate movement of the sleeves into firing position about the round.

The above and other features and objects of the present invention will be better understood from the following detailed description of the typical embodiment illustrated in the accompanying drawings in which:

Fig. l is a plan view of a machine gun constructed in accordance with the invention;

2,851,927 Patented Sept. 16, 1953 ICC Fig. 2 is a fragmentary representation of a belt of ammunition for the Fig. 1 gun;

Fig. 3 is a side view of the gun, not including the main mounting cradle;

Fig. 4 is a front view of the Fig. 1 gun;

Fig. 5 is a transverse section taken on line 5 5 of Fig. 3;

Fig. 6 is a longitudinal vertical section taken essentially on line 6-6 of Fig. l, but showing only the camming mechanism for actuating one of the ammunition feeding sprockets;

Fig. 7 is an enlargedfragmentary axial section through one of the tiring chambers, taken on line 7-7 of Fig. 1, and

Fig. 8 is a developed sectional view showing the conguration of the cam groove in one of the sprocket actuating sectors, and taken on the line represented at 8-8 in Fig. 6.

In the drawings, there is shown at lil a double barrel machine gun adapted -to fire a series of rounds of ammunition such as are shown at 11 in Fig. 2. The gun includes a main rigid body structure l2 which rigidly carries the two forwardly projecting barrels 13, and which is mounted for recoiling movement within the usual cradle typically represented at 14. The recoiling movement is yieldingly resisted by recoil springs 15, each of which bears at its opposite ends against a shoulder 16 formed on the cradle, and a lug li' which projects laterally from body structure 12. The two firing chambers for the barrels are formed by and within a pair of front and rear firing chamber sections 18 and i9, which are actuable relatively axially apart for movement of the ammunition rounds 11 into and out of the secti-onally formed firing chambers. Such actuation of the ring chamber sections is produced by a number of pistons Z0 which. are operated by gases bled oi from the barrels 13 on firing. The ammunition is fed to the tiring chambers by a pair of sprocket wheels 2l, which are actuated by and in timed relation with the axial movement of firing chamber sections 13 and 19, by means of a number of swinging gear segments 22 which engage bevel gears 66 attached to shafts 24 which carry the sprocket wheels.

With particular reference now to Figs. 2 and 7, the ammunition rounds handled by the present gun are of -the telescoped type, in which the projectile 25 is initially entirely contained within the tubular preferably metal cartridge case 26. This cartridge case has an-annular groove at its longitudinal center, anda rigid metal gas sealing ring 28 -is contained within that groove. As seen in Fig. 7, the outer surface of this ring 28 preferably has a slight axial taper toward the opposite ends of the shell,` and also the cartridge case itself 26 is tapered toward its opposite ends. Successive rounds 11 of the ammunition are interconnected in belt form by suitable links, preferably comprising -a number fof short exible high strength cables 29, whose ends may extend into the cartridge case through ring 2li and carry enlargements within the case for firmly attaching cables 29 to the various rounds. The powder charge is contained within a chamber 30 at the rear of projectile 25, and also within an annular chamber 31 about the projectile formed between cartridge case 26 and an inner preferably combuspair -of transverse forward and rear members 36 and 37.

Parts 35, 36 and 37 may be attached together in any suitablev manner as by screwsy 38. The two parallel ringbarrels 13' extend rearwardly through and beyond openings in the forward transverse body member 36, and are rigidlyattached to member ,36. Spaced rearwardly fromand in axial alinerrient with barrels I3, therear transversemember 37 of body'1'2 carries a pair of breech blocks "39 '(see'Figs. 1 and 7), whichareixedrelat-ive to the body l2, and have forward transverse `facesf40-for engaging the rear ends v'of the roundsff11'upon 'ring. Each"'breech"block"39 contains a central electrical-'contact 41, which engages primer 34 to `tire a round when thej'ringcircuit is closed.

"The-:forward 'ring Vchamber section`18 contains .two spaced 'parallel 'bores "42, which receive' 'the'forward end portions 43 ,of the two gun barrels 13 respectively (see Fig."7). `-`If' desired, each of the barrels may include Ya rear' `replaceable ring "44 which is `f`rictionally held rin vfixed relation to the main portion `of the barrel. By virtueof its-reception 'about the rearends of --the barrels, section 18'is axially slidable relative'to'the barrels,.but .at the same time' is a close enough lit about'the barrels'to form essentially a gas tight seal between these parts.

"The rear vtiring chamber section 19 is similar to forward section 18,V and contains two spaced parallel bore-s 45 alined'with' bores 42 of the forward section and receiving the externally cylindrical forward ends of the two breech blocks 39. 'As' will 4be apparent, section 19 is slidable rearwardly relative'to breech blocks v39, and'is afclose enough t about the breech blocks to form agas tight seal between theseparts. The bores 42 and 45 Vwithindiring chamber sections 18v and 19 are cylindrical along almost theirentire'extent, and of a diameter slightly vless than lthe external diameter of ring 28 on each of Vthe ammunition rounds. bores 145 areslightly outwardly lat 46,,essential1y in correspondence with theV taper of the outer -surface of ringl28, to tightly engage the tapered ringsurface vand thusform a very etective'gas tight seal between ring`28 andthe inner ends of sections 18 and 19. In their `firing position of Fig. 7sections 18 and 19 are spacedashort distance Jaxially apart, so that sprocket wheels'21 may remain in engagement with the roun'ds beingfre'd. After simultaneous tiring of two of the rounds in the' twofring chambers, sections 18 and 19 are actuated Vvrelatively axially apart, so that sprocket wheels 21 may displace'the emptycartridge cases from the firing chambers andfeed new rounds laterally into tiring positions 'within' the chambers. l.The sections 18 and 19 vmay then close'rfor tiring' of the two'new rounds.

4The' sections 18 and 19 are intermittently actuatedtrelatively *axially lapart by the force :of some of'the gases which are produced by the rounds upon'ring. VIForfthis purpose, the two barrels 13 have in their side'walls'the usual'bleed passages 47, through which some of th e gases'ow into a passage 48 communicating with a oparr of upper and lower lines 49, which connect'into a' pair-of upperand lower cylinder blocks 50 and-51. "Each'of these two blocks 50 is mounted in xed relation to body structure 12, as by forming the blocks to have integral shaft-'like projections 52 extending in opposite axial'directions and connecting rigidly to the transverse body-members 36` and 37.

`=Each cylinder block 501contains a first cylindricalibore 53 vwhich opens forwardly, r and contains a piston 54 adaptedl to be actuated forwardly 'against a laterally projectingflug 55 on section 18, to actuate 'fsec'tion`1'8iforwardly.

"Gases Vfrom line 49 'are communicated through'a "passage 56 inblock 50'to therear end of 'bore"53,"to" thus actuatepisto'n-54 and section 18 forward-ly. TSim'ilarly,

each of thecylinder blocks "Stl'containsafsecondpiston 57,*which isslidable within a rearwardly openingbore 58, and "which is'a'dapted to `beactuated rearwadlyiagainst lug`v59 ofA section- 19, -tomove '-section' 19 frearwardly. Gases 'from1-1linel49f arev of course suitablylintroduce'd into Atthe adjacent ends of sectionsV '18' ai1"d"1'9,'`

- and 37 at first ends of the springs, and the sections 1'8 and `57,' by a port '60' leading into bore S'Sfrom passage 56.

' arcuate irecessesi64,"adapted to' receive :and 'cont-rol'-the `bersection'=1-9 are received withinthe cam'gr'ooves the gun are vshaped and swing reversely#withfrespecttto fand 19 together and'rapart' serves lto intermittentlyswin'g the forward end of cylinder 'bore 58, `forwardly of piston Such gas pressure induced relative axial separation of sections 18 and 19 is yieldingly resisted by a number of coil springs y61 bearing at rst ends against body members 36 and 37, and bearingkat second ends against integral lugs 62 formed on sections 18 and 19. At the f end ofl ftheirela'tive 'separating movement v of the is'ections 18 and 19, `an increasedresistance I'to-thelseparating movement is oiered by four relatively strong butter usprings:63 which are disposed about the shaft-like portions'-`52.,of cylinder block parts 50, and'which engage v.elements'fl 19 at the opposite ends of the springs. Pheyelding re- .t sistance offered lby Aspringsnl is of course sufficient to maintain sections 18 and 19 in their Fig. 7 firing positions until the force of the gases has effectively propelled projectile 25 forwardly through and from thebarrel to thus avoidloss' of anyof the efectiveforce of the gases. .,.A'fter the sections 18 and 19`l1ave been urged :partbyfthe,;.g'z1s` force, thev pressure of'thejgases of course redluces immediately, 'and springs 61 are then eective toreturn'sec-l tions 18 and*19 relatively togethenfor the nextringloperation.

Whilefsections 18 and'19 arein 'their axially separated -V positions, sprocket wheels '21 act'to` advance'theired cartridgecases outof 'firing positions, and to feedthene'xt successive rounds to those positions. VThese Vsprocket f wheels 21fmaybe shaped substantially Yas' 'shown[inlFigL` 5, ieach'typically"having four circumferentially"spaced positioning of' successiverounds l11.k Sprocket wheels paral'l'elto the gun barrels. VAs previouslymetionm sprocket wheels 21 are receivedaxiallybetwe'en 18 and l'19. Thelatter twosections' vcontain"bores""`65 throughwhich shafts 24 extend, sothat'the shaftsard journalled "forA rotary movement by rsections "218 :and "19, andyet sections 18 and 19are1free'foraxial'niovemht relative to shafts 24. A-t its oppositeen'ds, eaclro'fi'the two shafts 24'carriesa pair of beveligearsl 66,"eatlrlcf"V which meshes-'with an 'arcuate'A series of teeth 67 (seeFiygs. f l Aand-'6) 4on one `of the gear segments 22. 'Thefgearsl `f are lc )perativelyy connected to'shafts 24 byoneway clutches 73 *of `any Aconventional construction. These 'clutehes73 are'ffec`tive totransmitrotation'from each ofitheffgers 66 'to' the corresponding shaft 24-ina"directionforniovingA Fthe associated-sprocket lwheel 21 `in an ammunition advancing f direction, but the clutches will An'ot"tr`ansrliit" reverse rotation. "These-gear .segments 22 havefthe-'shape` illustrated in Figh, and aremounted by screws*68 `to swing vertically alongl the inner sides of the ftwo"vertical side-plates 35 of body 12'. Apair of "springs69 ,yiel'dingly large-gear 4segments 22 downwardly"tontheirFigQ 6f1'1`ll line positions, :and yieldingly resist upward swing-Y ing movement of those segments to their brken'line'positions -Of-Fig. `6. In the inner face of each'ofthe gear" segments 22 there is provided an endless cam 'groove`f70r A having the configuration shown in`Fig.'6, andintowhich n lthere projects laterally a Ipin'71 which is `carried by-either Isection-'18 or-.section-.19, `and is springpressed-latrally byaspring 72`into groove 70. As'- will ybeapparent'from Figs. Lando, the pins' 71 carried "by the lrearir'ing'fchamthe' two 'rearxgear sectors 22, while the pins 71 :carried section 1-8'Iarek received -within the -cam grooves' 170 in *they 4forwardlgearI-sectors. It will also be-notedfrom"'Fig:l"6 that'lthe forward-and rear -cam `sectorsonfeach sides f Y each other.

The' .".'shape izo'ffendless cam "g'roo'ves 70 *in t' sectors? 22 is -vsuchthat Ethe s'relative faxial movement 'off sectionalv 18 `one direction and then in the other direction. The one- Way clutches 73 cause the rotation of gears 66 in one direction to turn shafts 24 and sprocket wheels 21 in a direction for advancing the ammunition toward the tiring chambers, while the reverse rotation of gears 66 does not turn shafts 24 and sprocket wheels 21 in a reverse direction. Y

As the ammunition is fed to the two firing chambers of the gun, the two belts of ammunition advance laterally into engagement `with sprocket wheels 21 through a pair of ammunition guide chutes 74 (see Fig. 5). These guide chutes may of course be attached to 'body structure 12 in any suitable manner.

`To now describe the operation of the gun, assume that the gun is in a condition in which two belts of ammunition such as that `shown in Fig. 2 are threaded into the two feed chutes 74 from opposite sides of the gun, and a leading round of each belt is in Ithe Fig, 7 iiring position within the corresponding firing chamber. With the parts in this condition, `an operator may close the ring circuit, to feed current to the primers 34 of the two rounds which are in ring position. This of course fires those two rounds, causing the powder charges and element 32 to burn, forcing projectiles 25 from the two rounds forwardly through the barrels and out of their forward ends. The engagement of the tapered surfaces 46 on sections 18 and 19.with the correspondingly tapered surface-s on rings 28 effectively seals the two firing chambers against the leakage of any of the gases from those chambers.

After the projectiles pass the location of bleed ports 47 in the barrels, some of the gases are allowed to vent through those ports and passage 48 into line 49, to actuate pistons 54 and 57. This gas pressure causes pistons 54 and 57 to actuate section 18 forwardly and section 19 rearwardly (the relative separation of these sections commencing after the projectiles have left barrels 13). When the sections 18 have moved suiciently far apart to allow the cartridge cases 426 of the two fired rounds to be removed from the tiring chambers, sectors 22 become effective to cause rotation of sprocket wheels 21 for moving the fired cases out of the chambers and advancing other rounds into the firing chambers. The sprocket motion then stops, while sections 18 and 19 again move relatively together toward their Fig. 7 firing positions, so that the second pair of rounds may be fired. If desired, there may be provided in the firing circuit an automatically operated switch for closing the firing circuit as sections 18 and 19 reach their firing positions. This control switch is represented typically at 75 in Fig. l, and may be considered as including a movable actuating element adapted to be engaged and actuated by a lug 76 on section 19. The firing circuit may include a suitable power source 77 (see Fig. 7), a trigger operated switch 78, and the automatically operated control switch 75.

To now describe somewhat more particularly the manner in which the movement of pins 71 with sections 18 and 19 functions to actuate gear sectors 22 and sprocket wheels 21, assume rst that pins 71 are in their Fig. 6 positions, with sections 18 and 19 in their Fig. 7 firing positions. As sections 18 and 19 and pins 71 commence to move relatively apart, the pins first advance within the straight horizontal portions 79 of grooves 70 in sectors 22, and because these portions are at that time horizontal, this initial pin movement does not cause any actuation of gear sectors 22. Thus, during that portion of the separating movement of sections 18 and 19, sprocket wheels 21 and the controlled ammunition belts remain stationary. When pins 71 reach the location of inclined portions 80 of grooves 70, the inclination of those grooved portions causes pins 71 to commence camming segments 22 upwardly. Such upward movement of segments 22 causes the engaged gears 66 to turn shafts 24 and sprocket wheels 21 in a direction for advancing the sprocket wheels and engaged ammunition. This advancement of course occurs only after sections 18` and 19 have moved relatively apart far enough to allow such advancement of the rounds. When each pin 71 reaches the outer end portion 81 of its groove 70, the pins commence to move relativelytogether along inwardly inclined parts of groove 70, and the angularity of these portions 82 of the grooves is such as to continue the upward deflecting movement of sectors 22. At the` specified portion 81 of each groove, the corresponding pin 71 advances past a step or shoulder 83 formed in the groove to move into a deepened portion of the groove under the influence of spring 72, to thus require the pin in its returning movement to follow branch 82 of the groove rather than branch 80.

After passing through branch 82 of the groove, the pin reaches a nal portion 84 of the groove, which portion is at that time extending parallel to the direction of movement of the pin, so that the pin is able to move along portion 84 of the groove without further actuation of segments 22. Thus, the iinal inward movement of pins 71 occurs without advancement of the ammunition. It will of course `be understood that the juncture of breeches 82 and 84 of groove 70 is so located as to stop the advancement of the ammunition by the time sections 18 and 19 reach locations at which they commence to enclose the rounds which are then located at the ring positions. As pins 71 reach the innermost ends of portions 84 of the cam grooves, springs 69 are able to return segments 22 downwardly to the full line positions of Fig. 6, so that the rounds in tiring position may be tired to commence another cycle of operation. Such downward movement of segments 22 is effective to turn engaged gears 66, but does not turn shafts 24 and sprocket wheels 21, since one-way clutches 73 will not transmit rotation in this reverse direction.

I claim:

1. A machine gun comprising a barrel, a breech assembly at the rear of said barrel forming a tiring chamber for holding a round of ammunition at a firing location, said assembly including two sections having tubular sleeve portions adapted to extend about and contain opposite ends of a round and mounted for axial movement relatively toward and away from each other and relative to the barrel between a first position in which they form said chamber and second relatively separated positions in which a round may move transversely to and from said firing location, means for alternately actuating said sections relatively toward and away from each other and relative to the barrel to re successive rounds of ammunition, means for tiring said rounds while the sections are in said first positions, and means for advancing successive rounds of ammunition to said tiring location While the sections are in said second positions.

2. A machine gun as recited in claim l, in which said means for actuating the sections comprise means actuable by the force of the gases produced by said rounds to separate the sections on each ring.

3. A machine gun as recited in claim l, in which said means for actuating the sections include gas operated piston and cylinder means for actuating the sections relatively axially apart and relative to the barrel, means for conducting some of the gases produced on ring from said barrel to said piston and cylinder means to actuate the sections apart, and spring means for returning the sections relatively axially toward one another.

4. A machine gun as recited in claim l, in which said sleeve portions of the sections both extend about a round to approximately the center of its axial extent.

5. A machine gun as recited in claim 1, in which there is a short space between said sections in said first positions through which there extends a connecting link between a round at the tiring location and a next successive round.

6. A machine gun as recited in claim l, in which a forward one of said sections in said second position slides forwardly about a rear portion of the barrel.

' upon Af1ring,la rear one `of said-sections in saidsecond position beingfslidablelrearwardly -to asaid breech block.

`9. y-A machine-gunasrecited in claim'1, in which said position about breech assembly rincludes abreechtblock-at 'the reary of saidring location for-backing Aup the -rear of-a round upon firing, arear one oflsaidfsec'tions .insaid second position being slidable rearwardly Y' tofamposition about said breech block, theforwards'se'ction-in said second position being 'slidablei forwardly about' afrear portionL of the barrel, there Ybeing -a vspace Vlaxially *between* said-:sections v`in said-rst positions throughlwhich 'links' interconnecting successive rounds extend.

`'10. A machine gun as recited-in claim'9, in Whiclr said sections extend to approximately'the vcenter ofthe-axial extend of acontained round and `have endfportions-annularlyvengageable inv gas'tight sealing relation evvfi-thean annular seal `ring on the round.

'11. A machinel gun as'recited in claim l'10,infvv-l1i'ch sid'means `for Jactuating'the sections comprise-means actuableby the force foff'the gases producecllbyesaid rounds 1toseparate'the sections on--eachiiring, saidro'un'd advancing means including aroundifeeding sprocket; and

means actuable bysaid movementlof the sectionsto tum thefsprocketffor feeding the-roundsesuccessively^to`-said firing location.

125A- machine gun'as recited in lclaim I'1,'inc`zli1ding `r means operable by said movement of the "'sectionsf'fo'r n actuating said round advancing means.

13.A-\machine gun as recited in claiml, in"which said round-advancing means 'includea roundffeeiding sprocket, yand cam means actuableby the axial 'movement l 1 of said sections for rotating said sprocket.

14. Amachine gun as recitedin claim 13,-"in which, said cam means include a gear for drivingthe sprocket, t faswinging gear sector forVV actuating saidgear, ando a pin 1 projecting'from one of said sections into a "carnyg'roove Y in 'said sector to Vactuate it in accordance with axial movement of the sections.

References Cited `in they ile of this patent 

